The present invention relates to integrally molded video cassettes. Specifically, the present invention addresses dust doors integrally hinged to video cassette covers.
The molding of dust doors on video cassettes with living hinges is a recent advent in the art of video cassette manufacture. The impetus behind providing a dust door in integral relation with a video cassette is primarily reduction of labor, reduction of parts, accuracy and simplicity of manufacture associated therewith, recyclability of the substantially uniform cassettes, and further improvements in the art of molding. Through continued testing of this technology, it has been shown that further improvements in conjunction with the hinges improve performance of the video cassettes and the dust doors when moving into opened position in a player and into closed position when removed from a video cassette recorder.
Several important goals exist as with previous devices. One relates to the ability of an integrally molded hinge to maintain strength well beyond the life of the video cassette. Previous hinges were relatively wide to maintain elasticity and resist breakage. However, it has been found that the width previously thought necessary to maintain hinge strength may cause jamming of the cassette within a small number of machines because of a hold down spring clip, platen or roller moving into depressions by the hinges. When the cassettes are inserted into video cassette recorders, tops of cassettes are held downward while the dust doors are moved upward to expose the video tape. Upon removal of the cassettes, spring clips or rollers in the machines slide across the top surfaces of the covers of the cassettes and over the dust doors. It is typical for dust covers to have short side portions which are hinged to the cassette side walls in indentations or cavities along the sides of the cassette. The indentations approximate the thickness of the door side portions. If those indentations are made too wide, as was previously thought necessary to accommodate wide hinges, the hold down spring clips can slip into the wide recesses and can jam a cassette or machine or prevent raising of the doors.
The hinges are attached to sides of the dust doors. The angles of the hinged extensions are important for proper functioning of the spring clip. A severe angle can cause jamming. The present invention addresses the potential problems of jamming due to wide hinges and severe angles in dust door hinge arrangements.
Another problem solved by the invention relates to the detection of tapes which have not been rewound. With prior cassettes, the user or rental employee had to lift the dust door to see if the clear leader was present, thus indicating a fully wound tape, or otherwise look through a clear window inserted in the cassette's cover.
The present invention also provides solutions to previous problems related to supplemental spring arrangements for dust door biasing.